Composition for treating materials



2 5 2 1 4 8 CROSS REFERENCE EXAMlNER United States Patent 0 3,147,244 COMPOSITION FOR TREATING MATERIALS Byron E. Marsh, Brookfield, Eric Jungermann, La Grange, and Charles E. Tippett, Chicago, 111., assignors t0 Armour and Company, Chicago, 111., a corporation of Delaware No Drawing. Filed Apr. 5, 1961, Ser. No. 100,829 7 Claims. (Cl. 252-136) This invention relates to compositions for treating metals and to processes for treating metallic surfaces with such compositions.

It is well-known that aqueous acid solutions are utilized for removing scale or film from metallic surfaces, as in de-scaling, boiler line tie-liming, and cleaning refinery equipment and oil wells.

For example, in the working of metals, particularly iron and steel, a scale or oxide forms on the exterior of the metal. So, it becomes necessary to clean the scale or oxide from the surface. In order to accomplish this, it has been the practice to treat the metal with an acid solution, such as hydrochloric, phosphoric, sulfuric, sulfamic and citric acids, although others are also commonly used. This method of cleaning metal surfaces, commonly called pickling, has been practiced not only on ferrous metals, but also on non-ferrous metals, such as aluminum, zinc, brass, etc.

Although the acid solution performs an adequate job of cleaning metal surfaces, it has been a problem that the cleaned metal surface becomes subject to corrosive attack from the acid.

It is therefore an object of this invention to provide a metal cleaning composition which is substantially noncorrosive to metals.

It is a further object of this invention to provide a process for cleaning metals, which process is effective but substantially non-corrosive to the metal being cleaned.

It is a further object of this invention to provide a metal cleaning composition which will act effectively in separating coatings and films from the metal surface While at the same time avoiding corrosive action on the metal.

It is a further object of this invention to provide a metal cleaning composition which is easily adaptable to industrial metal cleaning operations.

Further objects and purposes of this invention will become obvious as the specification proceeds.

We have now discovered new, substantially non-corrosive metal cleaning compositions which include essentially a quaternary ammonium compound having the general wherein R is an aliphatic hydrocarbon radical having from about 8 to 22 carbon atoms, R is an aliphatic hydrocarbon radical having from 1 to 3 carbon atoms, and X is a halide. These compounds are most effective in acid solutions.

Examples of aliphatic hydrocarbon radicals coming within the meaning of R are octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, tetradecenyl, pentadecyl, hexadecyl, hexadecenyl, heptadecyl, octadecyl, octadecenyl, octadecadienyl, octadecatrienyl, nonadecyl, eiocosyl, heneicosyl, and docosyl. It is preferred that this aliphatic hydrocarbon radical have from about 12 to 18 carbon atoms.

Examples of aliphatic hydrocarbon radicals coming within the meaning of R are methyl, ethyl, and propyl.

3,147,244 Patented Sept. 1, 1964 ice It is preferred that this aliphatic hydrocarbon radical have one carbon atom.

Examples of radicals coming within the meaning of the letter X are iodide, bromide, chloride, and fluoride. It is preferred that chloride be utilized.

Mixtures of the above described compound may readily be used in the present invention. The aliphatic hydrocarbon radical R may be derived from certain naturally occurring fats and oils, such as soy bean oil, coconut oil, tallow and the like. Tallow ordinarily comprises a mixture of the following aliphatic radicals: dodecyl, tetradecyl, tetradecenyl, hexadecyl, hexadecenyl, octadecyl, octadecenyl, octadecadienyl, and eicosyl. Coconut oil or cocoa ordinarily comprises a mixture of hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, octadecenyl, and octadecadienyl radicals. Soy bean oil or soya ordinarily comprises a mixture of hexadecyl, octadecyl, octadecenyl, octadecadienyl, octadecatrienyl and eicosyl radicals.

Many acids may be used with these quaternary ammonium compounds such as sulfuric, hydrochloric, phosphoric, sulfamic, and citric acids. It has been found that sulfuric and hydrochloric acids are particularly useful. Acid concentrations may vary greatly, although dilute aqueous acid solutions are usually used. Concentration of the acid solution will ordinarily range from about 2 to about 20% by weight.

The concentration of these quaternary ammonium compounds in the metal cleaning composition also has wide variation. However, it is preferred that the concentration be from about 0.01 to 2.0 weight percent, based on total solution. Optimum concentration of the inhibiting compound has been found to range from about 0.1 to about 0.3 weight percent, based on total solution.

In our non-corrosive process for treating, metals we contact the metal surface to be cleaned with the quaternary ammonium compounds above described. An aqueous solution of any of these compounds may be passed against the metal by washing, spraying or brushing, thus to clean the metal while at the same time avoiding corrosion and the formation of objectionable films, we find that the process is most effective when the treating solution is an aqueous acid solution of the special quaternary ammonium compound.

We have further found that dibutylthiourea may be added to the acid and quaternary ammonium compound. For example, good results are obtained with the quaternary ammonium compound and dibutylthiourea in an aqueous acid solution.

The following examples more fully illustrate the in vention, but it is not intended that the invention be limited to the exact procedures or concentrations utilized. Rather, it is intended that all equivalents obvious to those skilled in the art be included within the scope of the invention.

Example I Clean, weighed mild steel coupons were exposed to two solutions, one with the inhibitor and one without the inhibitor, for six hours. After the test period was completed, the coupons were removed from the acid solution, dried, cleaned and then reweighed. The corrosion rate of the coupons was calculated in pounds per square foot per day.

A 15% hydrochloric acid solution was utilized for both solutions. In the inhibited solution, 0.25 weight percent, based on total solution, of dimethyl dodecyl propargyl ammonium chloride was added at 200 F. In the uninhibited solution, the corrosion rate was 7.9 pounds per square foot per day, whereas the inhibited solution showed a corrosion rate of only .0305 pound per square foot per day. 1

Example 11 1 Test procedures were the same as in Example I, except that 0.3% FeCl was added to both acid solutions. The corrosion rate without the inhibitor was 8.25 pounds per square foot per day whereas with the inhibitor, the corrosion rate was 0.056 pound per square foot per day.

Example III Test procedures were the same as previously described, except that a 15% H SO acid solution was used. The corrosion inhibitor added was dimethyl, dodecyl propargyl ammonium chloride, the concentration being 0.3 weight percent, based on total solution. The corrosion rate without the inhibitor was 2.52 pounds per square foot per day, whereas the corrosion rate with the inhibitor was .099 pound per square foot per day.

Example IV The procedure followed here was the same as in Example III, except the inhibitor contained 3 parts of the quaternary ammonium compound and one part dibutylthiourea. The corrosion rate without the inhibitor was 2.52 pounds per square foot per day whereas with the inhibitor, including the quaternary and dibutylthiourea, the corrosion rate was .0169 pound per square foot per day.

Example V Test procedures were the same as before, except the acid solution was 15% hydrochloric acid. One of the acid solutions contained 0.25 weight percent, based on total solution, of dimethyl octadecyl propargyl ammonium chloride. With the inhibitor, the corrosion rate was .428 pound per square foot per day and without the inhibitor, the corrosion rate was 7.9 pounds per square foot per day.

Example VI Test procedures were the same as in Example V, except that 0.3% FeCl was added to each of the acid solutions. With the inhibitor, the corrosion rate was .590 pound per square foot per day, whereas without the inhibitor, the corrosion rate was 8.25 pounds per square foot per day.

Now that the invention has been described, we claim:

1. A substantially non-corrosive metal cleaning composition comprising an aqueous solution of about 2 to 20% by weight based on total solution, of an acid selected from the group consisting of sulfuric, phosphoric, hydrochloric, sulfamic and citric acids, and about 0.01 to 2.0% by weight based on total solution, of a compound having the general formula:

wherein R is an aliphatic hydrocarbon radical having from about 8 to 22 carbon atoms, R is an aliphatic hydrocarbon radical having from 1 to 3 carbon atoms, and X is a halide.

2. A substantially non-corrosive metal cleaning composition comprising an aqueous solution of about 2 to 20% by weight based on total solution, of an acid selected from the group consisting of sulfuric, phosphoric, hydrochloric, sulfamic and citric acids, and about 0.01 to 2.0% by weight based on total solution, of a compound having the formula:

wherein R is an aliphatic hydrocarbon radical having from about 12 to 18 carbon atoms.

3. A substantially non-corrosive metal cleaning composition comprising an aqueous solution of about 2 to 20% by weight based on total solution, of an acid selected from the group consisting of sulfuric, phosphoric, hydrochloric, sulfamic and citric acids, and from about 0.01 to 2.0% by weight, based on total solution, of dimethyl dodecyl propargyl ammonium chloride.

4. In a process for cleaning metal surfaces, the step of contacting the metal surface with an aqueous solution of about 2 to 20% by weight based on total solution, of an acid selected from the group consisting of sulfuric, phosphoric, hydrochloric, sulfamic and citric acids and about 0.01 to 2.0% by weight based on total solution, of a compound having the general formula:

wherein R is an aliphatic hydrocarbon radical having from about 8 to 22 carbon atoms, R is an aliphatic hydrocarbon radical having from about 1 to 3 carbon atoms, and X is a halide.

5. In a process for cleaning metal surfaces, the step of contacting the metal surface with an aqueous solution of about 2 to 20% by weight based on total solution, of an acid selected from the group consisting of sulfuric, phosphoric, hydrochloric, sulfamic and citric acids and about 0.01 to 2.0% by weight based on total solution, of dimethyl dodecyl propargyl ammonium chloride.

6. A substantially non-corrosive metal cleaning composition comprising an aqueous solution of about 2 to 20% by weight, based on total solution, of sulfuric acid, and about 0.01 to 2.0% by weight, based on total solution, of a compound having the general formula:

formula:

| RN-0Hz-GE0H X- wherein R is an aliphatic hydrocarbon radical having from about 8 to 22 carbon atoms, R is an aliphatic hydrocarbon radical having from about 1 to 3 carbon atoms, and X is a halide.

References Cited in the file of this patent UNITED STATES PATENTS 2,994,644 Wachter Aug. 1, 1961 3,047,510 Cizek July 31, 1962 FOREIGN PATENTS 858,719 Great Britain Ian. 11, 1961 OTHER REFERENCES Bolle et al.: Chemical Abstracts, Preparation of Quaternary Ammonium Derivatives (1955), page 10, 921b. Faster et al.: Acetylenic Corrosion Inhibitors, Ind. and Eng. Chem., volume 51, No. 7, July 1959, pages 825-828. 

1. A SUBSTANTIALLY NON-CORROSIVE METAL CLEANING COMPOSITION COMPRISING AN AQUEOUS SOLUTION OF ABOUT 2 TO 20% BY WEIGHT BASED ON TOTAL SOLUTION, OF AN ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC, PHOSPHORIC, HYDROCHLORIC, SULFAMIC AND CITRIC ACIDS, AND ABOUT 0.01 TO 2.0% BY WEIGHT BASED ON TOTAL SOLUTION, OF A COMPOUND HAVING THE GENERAL FORMULA: 